At least 5 million voters, predominantly young and from minority groups sympathetic to President Barack Obama, could be affected by an unprecedented flurry of new legislation by Republican governors and GOP-led legislatures to change or restrict voting rights by Election Day 2012.

Supporters of these new laws — spearheaded in six swing states, as well as other less competitive ones — argue they are just trying to stop voter fraud and protect the integrity of the vote. But opponents, mainly Democrats and Obama’s campaign, which is closely monitoring the daily warfare over the new laws, believe they are trying to change the face of the electorate in a way that benefits the Republican candidate for president.

Pennsylvania, New Hampshire, Virginia and Wisconsin, all viewed as important states this fall, each have enacted stricter ID laws. Florida and Ohio have cut back on early voting. And a whole host of other states have passed new ID laws as well.

As a result, millions of voters will find it much more difficult to vote on Election Day in November — some estimates, such as one from the Brennan Center of Justice last fall, put the number of those affected nationwide at more than 5 million. In Pennsylvania alone, the state’s Transportation Department released figures showing that more than 750,000 registered voters in the state — 9.2 percent of voters there — do not have the required forms of ID to vote in November.

“Swing states are always much more likely to have these kinds of laws restricting voting,” said Wendy Weiser, director of Brennan’s Democracy Program. “To the extent that it’s a political tactic to try and game the system, … it does make sense that that is where we see a lot of that because that is where it could make a difference to the outcome.”

The laws tend to disproportionately affect young voters and minorities — key Obama demographics — so the new restrictions will have an outsize impact on Democratic turnout. In Pennsylvania, for example, 18 percent of Philadelphia residents, who voted overwhelmingly for Obama in 2008, don’t have adequate IDs to vote in 2012.

Underscoring the measures’ racial overtones, U.S. Attorney General Eric Holder had harsh words for the voter ID measures more generally, calling them the equivalent of a “poll tax” at the NAACP conference in Houston earlier this month.

“I just don’t think it’s too onerous to pass [these laws] — our vote is our most sacred expression of our desire for our country,” said Catherine Engelbrecht of True the Vote, a group that advocates for more voter ID legislation.

Swing states that have passed voter legislation have seen strong legal pushback from Democrats and voting rights groups. For instance, the League of Women Voters and Rock the Vote have filed lawsuits against a handful of the stricter laws in Wisconsin and Pennsylvania, as well as other voting provisions in Florida.

Perhaps an even bigger complication than the laws themselves is that so much of the voter legislation around the country is in flux, and could still be by Election Day. Ongoing lawsuits are one factor in the uncertainty; other states require pre-clearance before the law’s implementation from the Justice Department under the Voting Rights Act.

“A lot of the damage has been done, in that there’s now great confusion among our voters and even among the poll workers about how elections run and what they need to bring,” said Heather Smith, president of Rock the Vote. “And an intimidating process has now become even more confusing. For a first-time voter who’s thinking about participating, … it is a demoralizing and confusing kind of message that’s out there.”

Educating supporters about how to be ready for Election Day is a major focus of the Obama campaign. The campaign has dozens of staffers in Chicago and in the states dealing with voting rights protection issues, a campaign official said. Those officials closely monitor the day-to-day developments in each state.

To streamline the information for voters, the campaign launched a site, gottavote.org, earlier this year that provides information about how to register in each state as well as what kind of documentation to bring to the polls.

State parties, too, are working hard to educate voters about what they need for Election Day, incorporating those education efforts into their voter registration and canvassing drives.

“As we’ve been out collecting signatures, we’ve also been canvassing, figuring out what groups are where, [whether] they need IDs,” said Graeme Zielinski, a spokesman for the Wisconsin Democratic Party. “For some populations, it’s a truth that things are difficult. It’s difficult for some people to get to the [Department of Motor Vehicles].”

Here’s POLITICO’s list of the most competitive presidential swing states that have enacted new voting restrictions this cycle and where those laws stand:

Pennsylvania

THE NEW LAW: The state’s new strict photo ID requirement was signed into law in March. The law requires a photo ID issued by the U.S. government or the Commonwealth of Pennsylvania, although a college ID card also counts. If voters do not have appropriate identification, they can cast a provisional ballot and must provide ID within six days of the election for their vote to be valid or sign an affidavit claiming indigence.

Pennsylvania Democratic Party Chairman Jim Burn said the new law “smacks of backroom politics and a Republican political agenda in an attempt to try and cheat.”

“It didn’t catch any of us off-guard or by surprise” when GOP state Rep. Mike Turzai said the law would give a victory to Mitt Romney, Burn said. “We’ve always known what the real legislative intent of this law was — trying to make the playing field uneven.”

WHERE IT STANDS: The law has come under fire from Democrats and voting rights groups in the state, and several groups, led by the American Civil Liberties Union of Pennsylvania, have challenged its constitutionality in state courts. The first hearing on the law took place July 25. The Department of Justice also opened an investigation into the law this month, questioning whether it discriminates against the state’s minorities. There’s a chance the state court could stay the law until after November, but as of now the new requirements will be in effect for the election.

Florida

THE NEW LAW: While Florida did not pass a voter ID law, it did pass a whole host of other voting laws that shorten the early voting period by several days, make it more difficult for people to change their registration between counties when they move, and add restrictions on third-party groups that conduct registration drives.

WHERE IT STANDS: The early voting provisions and changes for voters who move between counties are in effect in most parts of Florida, pending pre-clearance by federal court. The restrictions on third-party registration drives are on hold statewide after Groups like the League of Women Voters and Rock the Vote successfully filed suit against the state. That law is in effect in 62 of Florida’s 67 counties; it cannot be implemented in the other five until the state gets pre-clearance from Justice.

Virginia

THE NEW LAW: Virginia’s Legislature passed a new voter ID law that expands the types of identification voters can bring to the polls — including some types of ID that do not have a photo — but if voters do not bring one of the allowed IDs, they can only cast a provisional ballot and must bring their ID by noon on the third day to their local election office after the election for their vote to be valid.

WHERE IT STANDS: Passed and signed into law in May, the law is awaiting pre-clearance from Justice before it can take effect.

New Hampshire

THE NEW LAW: The new law was passed by the Legislature and vetoed by Democratic Gov. John Lynch; the Legislature overrode the veto and the new requirements were signed into law in June. Beginning in 2013, the state will require a federal or state-issued photo ID in order to cast a nonprovisional ballot; for 2012, however, the requirements include student IDs and other forms of photo ID.

WHERE IT STANDS: The law is awaiting DOJ pre-clearance; it will most likely take effect before November.

Ohio

THE NEW LAW: The Ohio Legislature passed a law that involves various voter restrictions, but the law was largely repealed. The only major provision still in place is that early voting ends, for all voters except military members and their spouses, the Friday before the election rather than the Monday before.

WHERE IT STANDS: The Obama campaign has filed suit in Ohio to try to restore the extra three days of early voting; it’s unclear whether those days will be restored before Election Day.

Wisconsin

THE NEW LAW: Wisconsin’s Legislature passed a strict photo ID law in 2011 that required voters to present a photo ID at the polls or cast a provisional ballot and present ID following the election.

WHERE IT STANDS: Various outside groups challenged the new voter ID law in federal and state court. A state judge found the law unconstitutional under the Wisconsin Constitution and has placed a stay on the law. Proponents of the law have appealed the decision, and there’s still a chance the law could go into effect before November.

North Carolina

THE NEW LAW: North Carolina considered a strict photo ID law, and the Republican-led Legislature passed legislation last year. Democratic Gov. Bev Perdue vetoed it, and the Legislature was unable to override the veto.

WHERE IT STANDS: At this point, it’s unlikely that North Carolina’s proposed photo ID requirements will be passed into law before November.